Grinding of gear-wheel teeth



GRINDING OF GEAR WHEEL TEETH Filed Dec. `27, 1927 1 IK, "rk r PatentedOct. 30, 1928.

UNITEDY STATES PATENT OFFICE.

HARRY HALES ASBRIDGE, F ASHTON-ON-MERSEY, ENGLAND, ASSIGNOR TO THECHURCHILL MACHINE TOOL COMPANY LIMITED, 0F BROADHEATI-I, NEAR MAN-CHESTER, ENGLAND.

Application led December 27, 1927, Serial No.

been made to determine the tooth form accurately. In particular Ireferred to Noyes British patent specification No. 107,608 in whichthere is described the use of a templet or cam corresponding in shape toone face of the tooth to be produced, this cam being secured to thespindle carrying the wheel to be ground and arranged to bear against afixed abutment. Motion of the wheel in one direction was obtained by theinteraction of the templet and abutment, Whilst in the reverse directionthe motion was determined by the action of a spring arranged to hold thetemplet in Contact with the abutment. I .also referred to a methoddescribed in the Lees Bradner Company British patent speciiication No.195,381. In this specilication there is described a double acting camfixed on the spindle carrying the wheel to be ground, the cam beinglocated between a pair of fixed abutments so that the cam determines theangular movement ot' the wheel positively in both directions of motion.v

My experience in the construction of gear grinding machines led me tothe conclusion that the maximum of advantages was associated with amethod involving the use of a single templet or cam in combination witha single fixed abutment, a spring being employed to keep the templet incontact with the cam during the return movement of the wheel. In theform previously employed by Noyes, the mechanism employed for carry@ ingout this method suifered from a serious disadvantage which rendered themethod im practicable at high speeds, the disadvantage being due to thefact that large movements had to be imparted to the spring. As describedin my previous specification I succeeded in solving the problem of theNoyes method of procedure by the use in conjunc- GRINDING OF GEAR-WHEELTEETI-I.

242,801, and in Great Britain October 18, 1927.

tion with the spring, of a movable support or carrier, the movements ofwhich were coordinated with those of the slide carrying the toothedwheel to be ground. By such invent tion I was able to employ a singletemplet and fixed abutment in a machine capable of producing accuratework at a high rate of speed, and machines made in accordance with myprevious invention have been put into successful operation. So long asthe machines are required only for wheels of comparatively 00 smalldiameter, no difiiculty is encountered, but for dealing with wheels ofcomparatively large diameter the invention forming the subject of myprevious British patent above mentioned results in a machine which iscostly and is undesirably large. I have, therefore, reverted to theproblem of the single templet and have devised a new form of springcontrol which enables the desirable simplicity and compactness to bereadily obtained in machines adapted particularly for wheels ofrelatively large. diameters.

The present invention comprises the employment in combination with asingle templet, an abutment for the same, and a spring one end of whichacts on the templet, of a cam or reaction member which is acted on bythe other end of the spring and is movable rrelatively to the templet,and an abutment with which the reaction member co-operates.

Referring to the accompanying sheet of explanatory drawings Figure l isa side elevation showing diagrammatically one manner of applying theinvention to a wheel tooth grinding machine.

Figure 2 is a cross'section on the lines l, 2, Figure I, and Figure 3 isa cross section on the lines 3, 4.

In carrying the invention into effect as shown in the drawings, thespindle a to which is secured the toothed wheelv 2') to be treated iscarried upon a slide to which a vertical i reciprocatory motion isimparted in the usual way. The slide is omitted from the drawings toavoid confusion. The toothed'wheel o is 95 acted upon by the Hat face ofa grinding wheel, a portion of which is indicated by c. This wheelrotates about a vertical axis.

-When the base circle of the toothed wheel is used as the datum line inthe generation of the tooth form, the axis ot the spindle a isreciprocated in a plane at right angles to that of the grinding face ofthe wheel c, and the elements d, e which will be described hereafter arearranged with their centres on a tangent to the base circle of thetoothed wheel. Following the method described in the previouslymentioned Noyes Patent, a single templet 'f is secured to the spindle tthrough the medium of a sleeve Z, and this templet co-operates with theabutment roller e which is mounted in a lixed position on the frame ofthe machine. It will be understood that the coniiguration of the toothface is determined by the configuration of the templet f. Y

The templet f is maintained iirmly in contact with the abutment e bymeans or" a helical spring g contained in a housing 71, pivotallyattached to the templet Seeing that a relatively large angular movementis imparted to the templet in each reciprocation of the spindle af, iti'ollows that if the reaction to the spring g were provided by a lixedabutment on the machine framefthe spring would experiencecorrespondingly large movements. For the reason explained in my previousBritish patent speciiication, such a condition is impracticable when amachine is required to operate at a high rate oi' speed. According to myformer invention I solved this dit iculty by arranging the spring inconjunction with a carrier connected to the slide on which the spindle ais mounted.

According to the present invention I arrange alongside the templet f areaction member having a cam-shaped periphery t' which co-operates withanother ixed abutment roller (Z on the machine frame. The periphery ofthe member z' may be of the same configuration as that of the templetj", but strict accuracy in this respect is unnecessary as any shapewhich does not involve a large relative movement between the parts z'and is suitable. The cani member e' is connected to the spring g througha plunger and the spring g is put into an initial state of compressionin order that it may exert the required pressure on the part During thereciprocation of the spindle 0, both parts z' and f perform an angularmovement due to their interaction with the fixed abutments d and e andso impart the required angular movement to the spindle a1. It must beunderstood, however, that this movement is determined solely by thetemplet f, the part c' serving merely to maintain an appropriate stateot compression in the spring g. Any diierence between the conigurationsof the parts z' and f will result in corresponding relative movementsoit' those parts under the action ot the spring, and the latter willexperience a corresponding variation of length,

but as this can be made very small it introduces no inconvenience.

It will be apparent from the foregoing that by this invention I am ableto avail my self or the advantages ot' the single templet method ofprocedure and at the same time I am able to maintain in a very simpleand eiiective manner a comparatively constant state of compression ortension in the spring.

In the complete machine any convenient provision is made forreciprocating the spindle a and in conjunction with the spindle anyconvenient indexing mechanism may be em ployed for moving the wheel fromone position to the next after each tooth face has been treated. In theexample illustrated, the parts z' which are mounted on a sleeve Z aresecured to the spindle a through the indexing mechanism. One of theabutments d, e, preferably d, is made adjustable by mounting it upon ascrew operated carrier is as shown in Figure l.

The invention is not limited to any particular mechanical details, asthese may be varied to meet diliferent requirements. Also the inventionis not limited to the example above described. Though preferable, it isnot es sential to mount the part z' in immediate conjunction with thepart f as these two parts may be separated if desired and connectedthrough a spring and appropriate linkage or other mechanism. TWhilst Ihave described a machine in which the work spindle reciproca-tes in avertical plane, it will be obvious that it may be arranged toreciprocate in a horizontal plane, or any other plane, the relativedisposition of the grinding wheel axle being correspondingly changed ifnecessary.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is l. In machines of the type specified forgrinding gear wheel teeth, the combination comprising asingle templetarranged in operative connection with the toothed wheel, an abutmentwith which the templet co-operates, a spring one end of which acts uponthe templet, a cam member which is acted on by the other end of thespring and is movable relatively to the templet, and a second abutmentwith which the cam member co-operates, sub stantially as described.

2. In machines of the type specified for grinding gear wheel teeth, thecombination comprising a single templet mounted axially with and securedto the toothed wheel, a

Comprising a templet secured to and mounted coaxially with the toothedWheel, a cam' thereto, telescopic members in connection with the templetAand cam member respeetvely,a springlocated between said telescopicmembers, roller abutments cooperating with the templet and cam memberrespectively, and means for adjusting one of the rollers, 10substantially as described.

In testimony whereof I have signed my name to this specification.

' HARRY HALES ASBRIDGE.

